Knockdown cofferdam



June 21, 1927. 1,633,131

K. SCHOEN xuocxnown COFFERDAM Filed April 24 1926 3 Sheets-Sheet l I ENTOR.

BY 4W June 1927' K. SCHOEN KNOCKDOWN COFFERDAM- 3 Sheets-Sheet 2 Filed April 24, 1926 I VEN TOR Q A TTORNE Y.

Patented June 21, 1927.

UNITED STATES 1,633,131 PATENT OFFICE.

KARL SCHOEN, 0F WUERZBURG, GERMANY KNOCKDOWN COFFERDAM.

Application filed April 24, 1926, Serial No. 104,3595, and in Germany September 9, 1924. l

The purpose of this invention is to substitute iron for wood in the construction of coifer dams and the like to simplify and improve the securing of such dams to rock bottoms; to enable the dam to be used more than once, and to save time in the erection thereof by reason of its simplicity and ease of assembling, which are of great importance in northern countries, in which the time for construction is limited in winter to the short period of low water. Also the present construction makes it possible to dismount the dam in a short time when abnormally high water occurs, whereas wood dams have to be blown up in such event. By slight variations and additions, it is easily-possible to convert the iron dam into a durable but removable emergency dam,

A distinguishing feature of the dam, in accordance with the present invention, is that it consists of a series of plane frames of rolled sections, spaced apart like bridge beams,"the supporting posts of said frames being connected together by wooden or other beams, to which are secured in the usual way the boards for forming the 'dam walls. The supporting posts are secured in rocky bottoms by providing each of them at both ends with guide members connected by pipes, for the reception of a screw-bolt, which is inserted in a hole, made in the rocky bottom, with its lower enlarged wedge-shaped end, and,by tightening up a nut mounted on the upper guide member, coacts with an opposing wedge, likewise set into thehole. The

' wedge extension of the screw-bolt is, preferably, conical, the counter Wedge being a conical sleeve abutting the lower end of the guide member. The placing of the supporting posts of the frame-work is effected successively by the aid of jig frames, which are secured to the upright posts by set-screws or the like, to regulate the distance between adjacent posts, and are provided at their free ends with guides to receive the fresh posts to be set, which latter are thereby held in correct position against the current on the river bottom, so that the guide members and the connecting pipe for receiving the screwbolt can be usedto guide the rock drill.

The-accompanying drawings illustrate a form of the invention.

Figure 1 is a cross-section through the dam.

Fig. 2 is a section on line A.B of Fig. 1. Fig. 8 is a plan view of Fig. 1.

Fig. 9 is a partial elevation of a jig frame on a larger scale. j

Fig. 10 represents the erection of the dam. Each supporting post a and b consists of two channel-irons placed back to back and closed at their lower ends by an angle-iron i I apertured for the passage of the anchoring means into the'earth. On the upper half of the post a is. riveted an L-iron d, against which the diagonal strut e is supported. To guide the latter, a channel-iron w is mounted on the post directly below the L-iron. d. Strut e is pivoted to the lower end of post I) and carries at its other end a wooden beam 9, secured by bolts h, by means of which the efiective length of strut 6 can be adjusted to suit irregularities in the bed. To the upper parts of posts a and b are bolted angle-irons i, which carry the cross-beam l0.

The means for securing'the posts a and 7) I in the rock, consists of a pipe Z, made of soft material and slitted at several places in its lower end, its upper end being crewed onto the guide member m. The lower end of this pipe engages, a conical wedge-member n, the extension or stem 0 of which runs to the upper edge of the posts a and Z) and isthere provided with threads, on which screws a nut f, seated on the guide member 2), which closes the top of said posts. The screw-stem or bolt 0 is enclosed in pipe or sleeve g, p which 15 screwed 1n the lower guide member m and engages the guide member 3) at the top. The supporting posts of-the'several frames are connected together by wooden beams 1", secured theretoby two channel-iron sections 8 at eac'hpost. To the beams 7" the wooden sheathing is nailed, as usual. To the legs of the channel sections, which contact the post, are bolted clamp plates 6, which serve to locate and secure them. The posts a are provided, in their lower halves, with angles M, which serve, when necessary, to support the same by wooden braces. 7

Figures 7 to 9 show the jig frame Z which serves to set the posts in their correct position on the river. bed and to holdthem against the current until they are secured 

